The Great Cathedral is a series of obligatory battles and puzzles, with detours to find Sigils before progressing further. A trip-hop snare and synth is added to familiar music.

The numerous Elixirs and Stat Reels after boss battles, and the set of HAGANE Fluted Armor (minus Helm) are worth considering when preparing for the game's final battle. The Cathedral's eight Elixirs of Queens alone, at maximum effectiveness gives Ashley 32 more Hit Points, with Stat Reel bonuses potentially doubling that.

Ashley starts on the Ground Floor (Great Cathedral L1), but with no doors to the same level, and the Cloudstone elevator Fixated for the foreseeable future, his only path to progress lies down, into the Basement (Great Cathedral B1)

The remainder of the route through the Cathedral is similarly circuitous, going up and down levels before each floor is cleared.

If Ashley misses a jump in a room with a Cloudstone at floor level that goes down into another room, and falls down between the floor and the Cloudstone, he will not take damage and be returned to the entrance as usual, but fall to the lower room. This can work to the player's advantage when going to a lower floor, as it is not necessary to ride the Cloudstones down, if there is enough room to fall past them. It adds an additional price to accidental falls, though, as Ashley has to ride the Cloudstone back up before proceeding.

Iron CrabArms: Pincer. Mouth, Aqua Bubble. Legs: Tidal RushValens, Elixir of Kings 255/255. Elixir of Queens 1/255Unlike most other bosses, hitting is more likely when performing chains, at least the first one or two. Single hits tend to miss.

Like The Victor's Laurels room, the wall facing the water has collapsed, offering a view of a hazy sunset over the water and a natural stone cavern.

Killing the Iron Crab activates the Cloudstone Elevator to the second floor in the first room, Into Holy Battle.

The Cloudstone does not operate until the death of both Marid and Ifrit. This room gives access all the way up to the Third floor, once all the Cloudstones involved are activated, the route being The Victor's Laurels > Cracked Pleasures > Free from Base Desires > The Wine-Lecher's Fall. For this reason, it is usually faster to save outside in Plateia Lumitar than in

Like the Sanity and Madness room, one wall has collapsed, and the room looks out on the water through cracked masonry columns and natural stone arches.

Defeating the Djinn activates the Cloudstone in The Poisoned Chapel, although the Sigil to proceed further is not obtained until the Puzzle here, though an easy one, to get to the Chest, which is one Cube above the ground; destroy the Cube in the corner, giving space to come up behind the other cube and push it to the floor. Stand on it to open the Chest.

Optional Puzzle: Move a Cube next to the Chest so it can be opened:Jump into the pit and push the top box West. Stand on it and push a box East. Now push that Eastern box, and the middle one, both North. After that it is just a matter of lining up the two wooden boxes to stop the glowing slide cubes from sliding too far. Line them up with that center line of cubes, and let 'em slide.

Dead-end room, only accessible from The Acolyte's Weakness
The Skeletons will continue to spawn until the Lich is defeated, even if Ashley goes only one room away. Once the Lich is defeated, none of the three will spawn. The Lich has an impressively wide array of low level Area Effect spells. It wears all Silver Armor except for a Wizard Robe, and a Silver Shamanic Staff, none of which drops.

The pillars on the South Side will not help with getting across and are trapped; make the jump from the door level, but not at a Northwest angle; jump straight North and then hit the left button and grab on. The center platform leads to The Hall of Broken Vows. The North Platform leads to Free From Base Desires. Jumping to it, northeast, from the center platform or back is a lead pipe cinch. Jumping from the center to the South may require stepping on the column with the Curse Trap on it, so be sure to have some Angelic Paens or Grimoire Benir/Blessing spell

Flame DragonHead: Bite, Searing Breath. Tail: Tail AttackCalla Sigil, Sorcerer's Reagent 255/255. Exit to the South is locked with the Acacia Sigil from the Arch Dragon. Exit to the West leads to He Screams for Mercy. Exit to the North leads to Light and Dark Wage War

No enemiesLevers are very rare in this game, and cause a great deal of confusion to some players. Although there was one in the Wine Cellar, it was much more obvious than this one, especially since it opens a door far away, up on the Third floor in The Heretic's Story. The lever is in the Northwest corner of this room.

The gap is jumped easily with a Faerie Wing; it may or may not be possible without one. Invigorate is said to help, also, but if so it is not enough for players with low Agility. Low Agility is recommended for crafters who want to be sure of getting hit, to raise Affinity and Class on armor.

Optional Puzzle: Move a Cube next to the Chest so it can be opened:Push the Southern glowing cube West. Position Ashley carefully to push West a second time. Push it North, to fill the gap that the other cube would otherwise fall into. Push the other cube down, and then push it next to the first cube. Positioning again, as Ashley pushes the second cube South, and South again, then West, next to the ChestAnother, longer way: Push the Southern cube west then south. Push the other cube West, West, South, East, South, and West. Pushing it East, in particular, can require a good deal of care in positioning.

No enemiesPuzzle:Use Cubes to make a step up to gain access to the southern ledge. Push the eastern glowing cube south, then west. Push the wooden cube East, then the remaining cube South, over the other two, and down. On the lowest level, push it east, and then south to the wall and climb up.Door to the south, to What Ails You, Kills You, locked with the Palm Sigil

A spinning irridescent disc flies into Ashley's view from the shadows and stops, revealing the pattern of the half-sun, half-moon. It tips backwards, and the body of a Nightmare phantom, and a face similarly adorned with a symbol of duality, extends out from the disc.

No enemiesBasically two rooms in one: There is no direct passage from the upper to the lower level, within this room.

Lower level:

Exit to The Wine-Lecher's FallThe hyperactive Cloudstones can be passed with perfect timing or decent timing and Fixate. Where long jumps require the forward button to be held down before the jump, the opposite is true of short ones; jump then tap the directional button.Exit to Hopes of the Idealist

Upper level:

The North-South Cloudstone is activated by killing the Lich. The upper level door is opened with a lever in Light and Dark Wage War. Exits to and (locked with the Calla Sigil)

Cutscene after the battle: Sydney returns to the wounded Hardin, Callo Melrose, and the Duke's son. Guildenstern, having stabbed Hardin when his back was turned to more important business, prefers to gloat over what he perceives as Sydney's betrayal of Hardin; leading Mullenkamp to believe that their presence in the city was to find the Blood-Sin, when it was on Sydney's back all along. Sydney begs Hardin's forgiveness; Guildenstern gives an inspired accounting of his reasons for wanting the Blood-Sin to purge the 'suppurating' land of 'profiteers'.[1] Sydney feels the truth of the future Guildenstern seeks is a little different than he expects: "A tyrant always dies alone", he predicts. When Guildenstern, having already used the Dark on Sydney, promises to take what he wants by force, even the silent watcher Callo Melrose is moved to object; "If the soul is not true and fast, the rites are meaningless", she warns.[1]Lady Samantha calls out of the shadows, possibly to distract Sydney; he strikes her to the floor with the Dark and perhaps unwisely, turns his back on Guildenstern to teleport his allies to safety. Sure enough, just as he completes the spell, Guildenstern strikes again; vowing, as Sydney falls, to carve the Rood Inverse from his back.[1]

Guildenstern is Evil. And Evil Class, too. See Character Discussion
The Penultimate Transformation is very resistant to chains. It wears Silver Fluted Leggings, a Titan's Ring, and a Damascus Holy Win Great Sword, none of which ever drop

The Final Transformation can be chained. It is said that the Menu (triangle) or the Quick Menu (Left 2) can be accessed during the casting of Bloody Sin, which seems only fair, as it takes a long time to cast and is the developer's best chance to show players the Game Over screen.